raster



E. 0. EASTER.

R H EOSTAT.

(Application led Apr. 11, 1898.) (No Model.)

Patented Oct. Il, |898.

2 Sheets-Sheet l.

VII/lll BWI).

TH: Norms PETERS no. Pnoomno., wAsHmcn'oN Patented Oct. II, |898.

E. 0. EASTER.

No. 612,2l2.

R H E 0 S T AT (Application led Apr. 11, 1898.)

2 Sheets-Sheet 2.

(No Model.)

.NAME

me Nonms grens cu. Nom-uma4 WASHINGTON. n c,

UNITED STATES PATENT Orme,

EDIVIN O. RASTER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE RASTER CARBONRIIEOS'IA'I COMPANY, OF SAME PLACE.

RH EO STAT.

SPECIFICATION forming part of Letters Patent No. 612,212, dated October11, 1898.

Application iled April Il, 1898. Serial No. 677,203. (No model.)

To @ZZ whom it may concern:

Be it known that I, EDWIN O. RAs'rER, a

citizen of the United States, residing at Ohi- .exact description of theinvention, such as will enable others skilled in the art to which itappertains to malte and use the same.

lWIy invention relates to a novel construetion in a rheostat or electricheater, the object being to provide a device of this character in whicha large number of carbon or other non-metallic resistance-sticks can besecured, so as to limit the size of the device and to secure sufficientcontact-surface between said resistances and metallic contact-pieces toprevent the formation of arcs at such points of contact; and it consistsin the features of construction and combinations of parts hereinafterfully described and claimed.

In the accompanying drawings, illustrating my invention, Figure l is ahorizontal section of a rheostat 0r heater constructed in accordancewith my invention mounted on a faceplate, taken on theline l l of Fig.2. Fig. 2 is a rear elevation of the same. Fig. 3 is a view in elevationof a modified form of my rheostat. Fig. 4 is a detail sectional view onthe line 4 4 of Fig. 3. Fig. 5 is a section on the line 5 5 of Fig. 3.

The main feature of the present invention y consists in providing asuitable frame of the smallest possible dimensions in which a largenumber of parallelresistance-sticks can be iirmly secured and at thesame time electrically connected in series in any desired manner, andalso in such a manner that if one resistance breaks it can be removedand another inserted in its place quickly and easily. To these and otherends I provide two frames, each consisting of two side pieces l,connected by cross-pieces 2 .and 3,between which a number of sets ofresistance-sticks 4 are clamped by means of set-screws 5, passingthrough the cross-pieces 2 and bearing against the nearest of saidresistances 4 to clamp the entire set, of which said resistance formsone, against the cross-pieces 3, a layer of insulating material, such asmica, being interposed between said screw and said resistance-stick.

Each two adjacent resistances 4 are connected together at one end bymeans of oontact-pieces 7, interposed between the same, and areinsulated from each other at their other ends by means of insulatingmaterial 6, interposed between the same. Each of the resistances formingone set is thus connected at one end with the next adjacent resistanceon one side and at its other end with the adjacent resistance on theother side, thus forcing the current to pass over the entire lengths ofall resistances in one set. Said resistances may also be connected inseries `parallel or any other desired manner.

The adjacent sets of said resistances are also parallel with each otherand are insulated from each other and held in relative position by meansof layers S of non-conducting material. Each of said sets of resistancesmay form one resistance and be connected with one button of a switch inany suitable manner, or each set of resistances 4 may form a pluralityof resistances and be connected with two or more buttons of a switch ata corresponding number of places. To enable such connection to be madein the simplest possible manner, the contactpieces 7 at the points whereit is desired to effect the connection with the switch are made toproject beyond the ends of the resistance-sticks and are provided intheir projecting portions with setscrews 9, which are adapted to securethe wires thereto. The side pieces l of the said framesproject beyondthe cross-pieces 3 and are provided with iianges lO at their ends, bymeans of which they are secured to the rear face of a face-plate orswitchboard ll.

rlhe above-described manner of mounting and connecting the resistancesis obviously extremely simple and efficient, as it not only saves space,but at the same time insures suficient pressure at points of contact toinsure good contact and prevent formation of arcs'.

In Figs. 1 and 2 I have illustrated a rheo stat in which a single frameis mounted on the face-plate or switchboard, such frame having largecapacity, while in Figs. 3, 4, and 5 I have illustrated a rheostatconsisting of a IOO frame in which the resistances are adapted to bemounted in a similar manner, said frame being so constructed as toenable any desired number thereof to be mounted behind a face plate orswitchboard, thus enabling a rheostat of any desired capacity to beeasily constructed. The said frame consists of two end plates 12,connected together by means of cross-pieces 13 and enlarged adjacent thepoints of connection with said cross-pieces 13, as at 14, to receiveset-screws 15 in one of said plates 12 and to form bearing-surfaces onthe other of said plates 12, the sets of resistances being adapted to beclamped between said set-screwsl 15 and said bearing surfaces. Layers 16of insulating material are interposed between said sets of resistancesand said cross-pieces 13 and between said resistances andconfining-plates 17, secured at their ends to said plates 12 to holdsaid resistances in place.

My device has proved very efficient with the use of carbon or graphiteresistance-sticks, though other material may be employed to equaladvantage.

l claim as my invention- 1. Arheostat or heater comprising a frameadapted to receive a plurality of sets of resistan ces, each of whichcomprises a plurality of resistance-sticks alternated with contact andinsulating pieces, and means for clamping said sets of resistances insaid frame comprising devices mounted in one member and adapted to bearagainst said sets of resistances and clamp same against an other memberof said frame, substantially as described.

2. A rheostat or electric heater comprising a frame adapted to receive aplurality of practically1 parallel resistances divided from each otherby means of contact and insulating pieces,and means for securing saidresistances in said frame and holding same in close contact with saidcontact-pieces, consisting of a setscrew in one member of said frameadapted to bear upon one member of said set of resistances to clamp saidset against each other and another member of said frame, substantiallyas described.

A rheostat or heater comprising a plurality of resistance-sticks laidpractically parallel with each other, each of said resistances beingelectrically connected at one end with the adjacent resistance and atits other end insulated therefrom by means of conducting andnon-conducting pieces respectively interposed between said adjacentresistances at opposite ends, and clamping devices for holding saidresistances and said pieces interposed between the same in close contactwith each other, substantially as described.

4. A rheostat or heater comprising a plurality of resistance-sticks laidpractically parallel with each other, each of said resistances beingelectrically connected at one end with the adjacentresistance and at itsother end insulated therefrom by means of conducting and non-conductingpieces respectively interposed between said adjacent resistances atopposite ends, means for connecting said resistances with a face-plateor switchboard comprising projections on said conductingpiecesinterposed between said resistances to which wires are adapted to beconnected, and clamping devices for holding said resistances and saidpieces interposed between the same in close contact with each other,substantially as described.

5. A rheostat or heater comprising a plurality of resistance-sticks ofrectangular crosssection laid practically parallel with each other, eachof said resistances being electric ally connected at one end with theadjacent' resistance and at its other end insulated therefrom by meansof conducting and nonconductingpieces respectively interposed betweensaid resistances at opposite ends, a frame adapted to receive saidresistances, and means for clamping said resistances in said frame andin close contact with the interposed pieces, substantially as described.

In testimony whereof I ailix my signature in presence of two witnesses.

EDVIN O. RASTER.

Witnesses:

ERWIN J. LoTZ, WM. 13. SNownooK.

